A test score indicator for students produces a performance score based on a combination of...

  The correct answer is C, as three additional test cases are needed to ensure full coverage of all valid input equivalence partitions. Equivalence partitioning is a black-box test technique that divides the input domain into partitions of equivalent data from which test cases can be derived1. In this case, the input domain is the combination of the number of consecutive hours studied and the average intensity of focus on the material during the study time. The partitions are the possible combinations of these two factors. There are four possible values for the number of hours studied (below 4 hours, 4 to 8 hours, 9 to 12 hours or above 12 hours) and three possible values for the intensity of focus (low, medium or high). Therefore, there are 12 possible partitions in total. The given test cases cover nine partitions, as shown in the table below:

The missing partitions are marked with a dash (-). To cover these partitions, three additional test cases are needed, such as:

TC9: Hours = 4 to 8, Intensity = High

TC10: Hours = 9 to 12, Intensity = Low

TC11: Hours = 9 to 12, Intensity = High

References: 1, Section 4.2.3